3-alkoxy-14-acyloxydihydromorphinone derivatives

ABSTRACT

THE INVENTION RELATES TO NOVEL 3-ALKOXY, 14-VALERYLOXY OR CAPROYLOXY-DIHYDRONORMORPHINONE DERIVATIVES, WHICH AT THE NITROGEN ATOM ARE SUBSTITUTED WITH A CYCLOPROPYLMETHYL OR CYCLOBUTYLMETHYL RADICAL, AND THEIR ACID ADDITION SALTS; THESE COMPOUNDS SHOW VERY USEFUL PROPERTIES IN THAT THEY EXERT A SURPRISINGLY IMPROVED ANALGESIC ACTIVITY BESIDES TRANQUILLIZING, COUGH SUPPRESSING AND ANTICONVULSANT PROPERTIES, WITHOUT INDUCING DEPRESSING RESPIRATION.

United States Patent 3,828,050 3-ALKOXY-14-ACYLOXYDII-IYDROMORPHINONE DERIVATIVES William Roger Buckett, Lanark, Scotland, and Hans Harold Bosman, Epe, Netherlands, assignors to Akzona Incorporated, Asheville, N.C.

No Drawing. Continuation-impart of abandoned application Ser. No. 35,881, May 8, 1970. This application Aug. 7, 1972, Ser. No. 278,240

Claims priority, application Great Britain, May 16, 1969,

25,025/ 69 Int. Cl. C07d 43/28 US. Cl. 260-285 4 Claims ABSTRACT OF THE DISCLOSURE The invention relates to novel 3-alkoxy, 14-valeryloxy or caproyloxy-dihydronormorphinone derivatives, which at the nitrogen atom are substituted with a cyclopropylmethyl or cyclobutylmethyl radical, and their acid addition salts; these compounds show very useful properties in that they exert a surprisingly improved analgesic activity besides tranquillizing, cough suppressing and anticonvulsant properties, without inducing depressing respiration.

CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of application Ser. No. 35,881, filed May 8, 1970, now abandoned.

The invention relates to novel morphinone derivatives and more particularly to certain esters of 14-hydroxydihydronormorphinone derivatives.

BACKGROUND OF THE INVENTION Chemically the morphinone derivatives belong to the morphine and morphine-like substances. Morphine which is a strong analgesic has a disadvantage of readily inducing harmful morphine addiction. Nalorphine, an N- allyl derivative of morphine is known to have reasonable analgesic properties and to be a good morphine antagonist, but it has the undesirable side effect of inducing hallucinogenie phenomena. Generally the biological activities of the morphine-like substances are widely different.

An important improvement in the field of analgesic substances was the finding of N-substituted-l4-hydroxydihydronormorphinone derivatives reported in the Belgium Pat. 691,715. Said Belgium patent describes 14-hydroxydihydronormorphinone derivatives, substituted at the nitrogen atom with a dimethylallyl, cyclopropylmethylor cyclobutylmethyl radical. These derivatives show analgesic properties without remarkably inducing the known side effects accompanying the use of morphine.

SUMMARY OF THE INVENTION Surprisingly we have found that certain esters of 3- alkoxy-l4-hyclroxy-N-substituted dihydronormorphinone exert a strongly improved analgesic activity, both in oral as well as parenteral administration, in comparison with the corresponding non-esterified compound.

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The novel esters according to the invention have the general formula:

in which R is a cyclopropylmethyl or cyclobutylmethyl group, R is a valeryl or caproyl moiety, and R is a lower alkyl group with 1-6 carbon atoms,

as well as the acid addition salts thereof.

The novel esters show very useful analgesic properties. They are extremely valuable in post-operative treatment of patients, because of their analgesic, psychosedative, cough suppressing, anticonvulsant and lack of respiratory depressent properties.

The novel esters according to this invention can be prepared by esterification of 3-alkoxy-N-substituted-14- hydroxy-dihydronormorphinone with valeric or caproic acid or a functional derivative of these acids, such as the acid chloride, acid bromide or the anhydride.

3-Alkoxy-N-substituted 14 hydroxy dihydronormorphinone can be obtained in various ways. For example l4-hydroxy-dihydrocodeinone can be acylated in the 14- position, e.g. with acetic acid anhydride, in the resulting product the N-methyl group is then replaced by an N- cyano group by reaction with bromocyan whereupon the cyano group is removed with a strong acid e.g. sulphuric acid, thus yielding l4-hydroxy-dihydronorcodeinone. This latter compound is a suitable starting material to obtain the relative N substituted 14 hydroxy dihydronorcodeinones by means of reaction with cyclopropylmethylbromide or cyclobutylmethylbromide. An alternative method comprises conversion of l4-hydroxy-dihydronorcodeinone with glycol into the corresponding ethyleneketal which is converted in turn by reaction with cyclopropylcarbochloride or cyclobutylcarbochloride into the corresponding N-cyclopropylcarboxyl or N-cyclobutylcarboxyl compound which 'by subsequent reduction with lithium aluminium hydride followed by splitting off of the ethyleneketal group by boiling with acid yields the corresponding N-cyclopropylmethylor N-cyclobutylmethyl-14-hydroxy-dihydronorcodeinone.

Also the acid addition salts of the compounds with the general formula indicated belong to the present invention. Generally they are even preferred due to the better physical properties.

With acid addition salts are meant the salts derived from therapeutically acceptable organic or inorganic acids EXAMPLE IV 30 g. of N-cyclopropylmethyl-14-hydroxy-dihydronorcodeinone were dissolved in 50 ml. of toluene. 20 g. of butyric acid anhydride were added to the solution and the mixture was boiled with reflux for 11 hours. The toluene was distilled 01f and the residue was poured into water. The mixture was adjusted to pH 9 with a sodium carbonate solution and then extracted with benzene (5 times) The combined benzene extracts were concentrated to dry. Crystallization of the residue from an acetone-water (4:1) mixture yielded 18 g. of crude ester. Recrystallisation from the same solvent (fresh) yielded N-cyclopropylmethyl-14-butyryloxy-dihydronorcodeinone (m.p. 84.2- 85.4" C.).

EXAMPLE V 25 g. of N-dimethylallyl-14-hydroxy-dihydronorcodeinone were dissolved in 250 ml. of benzene. 31 g. of butyric acid anhydride were added and the mixture was boiled with reflux for 41 hours. The benzene was distilled off and the residue was poured into water. The pH of the mixture was adjusted to 9 with a sodium carbonate solution and extracted with benzene (4 times).

The combined benzene extracts were concentrated to dry and the residue was dissolved in 150 ml. of 3 N acetic acid. The acetic acid solution was adjusted to pH 2 with sulphuric acid and was then extracted with ether. On neutralization of the aqueous phase with a sodium carbonate solution 24 g. of a brownish yellow precipitate were obtained which, on recrystallisation from an acetone-water (4:1) mixture, yielded 17 g. of N-dimethylallyl-14-butyryloxydihydronorcodeinone (m.p. 82.0-83.5 0.).

EXAMPLE VI 30 g. of N-cyclopropylmethyl-14-hydroxy-dihydronorcodeinone were converted into N-cyclopropylmethyl-14- valeryloxy-dihydronorcodeinone in the same way as described in Example V but using valeric acid anhydride instead of butyric acid anhydride yielding 19 g. with melting point 95.5-96.5 C. Similarly N-dimethylallyl-14-hydroxydihydronorcodeinone yielded N-dimethylallyl-l4-valeryloxy-dihydronorcodeinone with melting point 102.4-103.6 C., and N-cyclobutylrnethyl-14-hydroxy-dihydronorcodeinone yielded N-cyclobutylmethyl-14-valeryloxy-dihydronorcodeinone with melting point 102-103 C.

EXAMPLE VII 59 g. of N-dimethylallyl-l4-hydroxy-dihydronorcodeinone were reacted with 51 g. of caproie acid anhydride in the same way as described in Example IH, except that the residue of the benzene extracts was dissolved in ethanol. To this ethanolic solution ether was added until turbidity just occurred. On standing in a refrigerator 33 -g. of N-dimethylallyl-14-caproyloxy-dihydronorcodeinone were obtained as crystals (m.p. 85.4-86.5 C.).

In the same way N-cyclopropylmethyl-14-caproyloxydihydronorcodeinone (mp. 102104 C.) and N-cyclobutylmethyl-14-caproyloxydihydronorcodeinone (mp. 108- 109" C.) were obtained.

6 EXAMPLE VIII 49 g. of N cyclopropylmethyl-14-hydroxy-dihydronorcodeinone were added to 140 ml. heptanoic acid anhydride. The solution was heated to C. with stirring and kept at said temperature for 2 hours. The mixture was cooled, poured into water, whereupon the pH was adjusted to 9 with a solution of sodium carbonate. The mixture was then extracted with benzene (4 times). The combined benzene extracts were concentrated to dryness. The residue was dissolved in ether and subjected to chromatography over neutral A1 0 The eluates containing ester were evaporated to dryness. Crytallisation of the residue from petroleum ether yields 47 g. of N-cyclopropylmethyl-14-heptanoyloxydihydronorcodeinone (m.p. 87.4-88.2 C.).

In a similar way but with recrystallization from an ethanol-water (4:1) mixture 32 g. of N-dimethylallyl-14-heptanoyloxy-dihydronorcodeinone (m.p. 66.0-67.2 C.) were obtained from 40 g. of N-dimethylallyl-14-hydroxy-dihydronorcodeinone.

What is claimed is:

1. N-cyclopropylmethyl-14-valeryloxy-dihydronorcodeinone and pharmaceutically acceptable acid addition salts thereof.

2. N-cyclopropylmethyl 14 caproyloxy-dihydronor codeinone and pharmaceutically acceptable acid addition salts thereof.

3. N-cyclobutylmethyl 14 valeryloxy-dihydronorcodeinone and pharmaceutically acceptable acid addition salts thereof.

4. N-cyclobutylmethyl 14 caproyloxy-dihydronorcodeinone and pharmaceutically acceptable acid addition I salts thereof.

References Cited UNITED STATES PATENTS 3,254,088 5/1966 Lewenstein 260-285 3,300,500 1/1967 Sawa et al 260-285 3,332,950 7/1967 Blumberg 260-285 3,654,280 4/1972 Sawa et al 260-285 3,676,557 7/ 1972 Lochman et al. 260-285 FOREIGN PATENTS 2,022,899 11/ 1970 Germany 260-285 OTHER REFERENCES Buckett et al.: Chem. Abstr., Vol. 74, C01. 88183y, abstracting German 2,022,899.

Currie et al.: Chem. Abstr., Vol. 62, C01. 2801n, abstracting British 975,602.

Seki et al.: Yakugaku Zasshi, Vol. 84, pp. 280-5 (1964).

Seki et al.: Yakukahu Zasshi, Vol. 84, pp. 255-257 (1964).

DONALD G. DAUS, Primary Examiner US. Cl. X.R. 424-260 

